This invention relates generally to Radio Frequency (RF) devices, and more particularly, to methods and systems for testing RF devices.
RF devices are used to send or receive electromagnetic signals. Examples of RF devices include RF coils used in Magnetic Resonance Imaging (MRI) systems such as surface coils. The surface coil is an antenna that is designed to transmit and/or collect signal from a specific region of the body. A surface coil, typically, includes multiple coil elements.
Over the past few years, the number of coil elements inside a surface coil has been increasing, making the structure of circuit inside it complex. A typical surface coil includes 8 to 64 coil elements. The number of coil elements in the surface coil is expected to increase further in future.
The surface coils undergo lot of stress due to handling and usage. Moreover, a complex structure of the surface coils makes its components more prone to failure. The surface coils undergo a variety of tests and quality control checks regularly to ensure safety of both patients undergoing MR investigations and instrumentation used in MRI systems. However, it is difficult to test individual circuits, such as decoupling elements and preamplifiers, present inside the surface coils. Moreover, operating conditions of the surface coils are affected by the presence of a testing device including electrical wiring in its vicinity.
Known methods use phantoms, to test the surface coils. A phantom is an object of a known size and composition that can be imaged to test or monitor homogeneity, imaging performance and orientation aspects of MRI systems. However, the test is subject to process variations such as the proximity of the phantom to individual coil elements. Multiple phantoms may be needed, one for each surface coil. Moreover the phantom may be required to be re-positioned on the surface coil to test alternate coil elements and combinations. Therefore, the test of a particular coil is time consuming and cumbersome.